Electro-magnetic typewriter



Nov. 18, 1958 A. E. AUERBACH 2,850,757

ELECTRO-MAGNETIC TYPEWRITER Filed Oct. 16,1956

INVENTOR.

United States Patent ELECTRO-MAGNETIC TYPEWRITER Abraham E. Auerbach, LaMesa, Caiif., assignor to Leon Fine & Associates, Highland Park, Ill., apartnership Application October 16, 1956, Serial No. 616,306

7 Claims. (Cl. 197-84) This invention is concerned generally with atypewriter, and more particularly with proportional spacing for anelectro-magnetic typewriter.

In accordance with standard practice, the same space is allotted on thetyped page by most typewriters, irrespective of the inherent width ofthe letter or character. Thus, for example, the letter i is a verynarrow letter, whereas the letter m is a relatively wide letter.Nevertheless, almost all typewriters allot the same space on the typedpage to both letters. Attempts have'been made heretofore to produce atypewriter having proportional spacing, i. e., a typewriter in whichvariable widths are allotted to letters in accordance with the width ofthe letters. For example, the letter i may be considered to be oneunitwide, the letter 0 two units, the letter w three units, and m fourunits.Such spacing gives the illusion of printing, and a page typed on such amachine is better looking and more impressive than one typed on anordinary typewriter. Unfortunately, however, prior typewriters embodyingthis feature have been inordinately expensive.

Accordingly, it is an object of this invention to provide proportionalspacing in a typewriter at relatively low cost. t

"A further object of this invention is to provide proportional spacingin a particular type of typewriter, wherein rebuilding of the typewriteris unnecessary, only .the addition of further parts beingrequired.

More particularly, it is an object of this invention to provide anelectro-magnetic typewriter with proportional spacing wherein a variablemagnetic path is used in connection with the type actuatingelectro-magnet to control the distance of carriage movement.

Other objects and advantages of the present invention will be apparentfrom the following description when taken in connection with theaccompanying drawings, wherein:

Fig. 1 is a fragmentary side view, partially in section,

of a typewriter embodying the principles of this invention;

Fig; 2 is an enlarged fragment of Fig. l

Fig. 3 is a horizontal sectional view taken substantially along thelines33 in Fig. 2; V

Fig. 4 is a view similar to a part of Fig. 3 and taken along the line 44in Fig. 2; t t i Fig. 5 is a view similar to a part of Fig. 3 andshowing a modification;

Fig. 6 is an electrical wiring diagram forming a part of the typewriter;and

Fig. 7 is a vertical sectional view taken substantially along the line7-7 in Fig. 2.

Referring now in greater particularity to the drawings, and first toFig. 1, there will be seen the usual typepatent application fortypewriter, Serial Number 581,-

writer platen 30 having a sheet of paper 32 in typing r positionthereon. The typing ribbon 34 is in its accustomed position in front ofthe sheet of paper, and on th8 opposite side thereof relative to theplaten 30. The mribbon may be held in any suitable or known manner,

2,860,757 Patented Nov. 18, 1958 and operated by known mechanisms. Aseries of type bars 36 (only one being shown) of more or lessconventional construction is pivotally mounted at 38. Hereinafter,reference will be made to the single illustrative type bar and theaccompanying parts. It will be understood that all parts are multiplied,where necessary, in accordance with the necessary number of type bars.More specifically, the type bar 36 has a type head or pallet 40 having atype face 42 thereon adapted to engage the ribbon 34 in order to form atyping impression on the paper 32. The type bar is provided with a slug44 of magnetically susceptible material such as soft iron, and this slugis mounted shortly below the type head or pallet by any suitable means.Conveniently, the slug would be welded or soldered in place. A stop orrest 48 is provided for all of the type bars to hold them in idleposition, such position being shown by the dot-dash lines of Fig. 1.

For each type bar 36 there is provided a key lever 50 pivoted at 52 andhaving an up-turned outer end carrying a key 54 of known construction. Astop or rest 56 is provided beneath the inner end of all of the keylevers, and a spring 53 for each of the key levers is provided to holdthe associated key lever against the stop. On the inner end of eachlever there is provided a pivotally mounted dog or jack 60, pivoted at62. This dog or jack is urged by a spring 64 toward a stop 66. Whenengaging this stop,the dog or jack bears upwardly beneath a shoulder 67on the type bar.

Depression of a key 54 and accompanying pivota movement of thecorresponding key lever 50 will cause the associated type bar 36 to bemoved upwardly from the dot-dash line position of Fig. 1, through thedashedline position, and into the solid line position in contact with,or substantially in contact with the ribbon 34. As the type bar 36approaches this limited position, the jack or dog 66 pivots against theforce of the spring 64 and slides off of the shoulder 67 as is shown infull lines in Fig. 1, thus freeing the type bar for partial return, asto the position shown in. dashed lines. However, the force with whichthe type bar is moved into proximity with the ribbon 34 is by design notsufiicient to make a typing impression, and additional means areemployed for this purpose as now will be described. 7

The foregoing is in accordance with mycopending 421, filed April 30,1956, and further in accordance with that applica ion, an electromagnet68 is positioned below the platen 36. The electro-magnet is providedwith a pole piece Til projecting toward the type bars, and is positionedso that the magnetic slug 44 of any type bar will be aligned therewith.The electro-magnet additionally includes an energizing coil 74, as willbe understood.

A nonmagnetic switch actuator or push member 76 extends across the topof the electro-magnet 68, and is mounted in any convenient manner (notshown) for reciprocating movement, i. e., movement from right to left orvice versa in Fig. l. The switch actuator or push member 76 ispositioned for abutment by an abutment section 78 on the type bar 36,and shortly below the type face 42. The switch actuator or push member76 conveniently is provided with an insulated tip 80, and switchcontacts 84 carried by resilient arms 86 insulatedly mounted on a fixedsupport 32 are forced into engagement when the resilient strips 86 aredeflected by engagement of the insulated tip therewith.

The electrical circuit as shown in Fig. 6 includes a full wave bridgerectifier 88 connected to a flexible cord 96 having the usual plug (notshown) thereon for insertion in any convenient electrical outlet. Thepositive side of the rectifier is connected to a junction point 92,while the negative side is connected to a bus 94. The

bus 94 is connected to one end of the coil winding 74, and the other endof the coil winding is connected to the fixed contact 96 of a relay )8.The relay includes a coil 100 wound on a core 162, and an armature 104attracted toward the core against the force of the spring 106 normallyholding the contacts of the relay open. The armature is connected to abus 108, and this bus is connected through a resistor 11d of high valueto the junction point 92.

One end of the relay coil 100 is connected directly to the bus 94, whilethe other end is connected through a wire 112 to one of the contacts 84.The other of the contacts 84 is connected through a wire 114 to thejunction point 92.

A capacitor 116 normally is charged from the rectifier 88 through thehigh resistance 114 When a key is depressed and the type bar 36 isthrown toward the full line position of Fig. l, in the manner previouslydescribed, the switch contacts 84 are brought into engagement. Thiscauses energization of the relay 9%, the armature 104 thereby closingagainst the fixed contact 96. This causes the capacitor 116, and any ofthe parallel capacitors .118 that might have been switched into thecircuit, to be discharged substantially instantaneously through theelectromagnet coil 74. This causes the pole piece of the core 70 toexert a sudden and powerful attractive force on the slug 34, and therebyto press the type face 42 against the ribbon 34 to form a typingimpression on the paper 32. Since this magnetic force is not applieduntil such time as the type face is in engagement with the ribbon, orvery nearly so, the type face acts to form the typing impression with apressing force with substantially no noise.

It will be appreciated that a given charge will be applied to anadjacent slug 44- when the single capacitor 116, connected between thebus 1% and the wire 94, is discharged. The additional capacitors 118 areconnectable in parallel with the capacitor 116 by the closing ofswitches 120. It will be appreciated that this causes a stronger impulseto be imparted to the adjacent slug, whereby a greater typing force isapplied to the ribbon. As will be appreciated, this renders it possibleto provide a greater number of carbon copies, or to form a more forcibleimpression, if such should be desired.

It will be appreciated that the resilient arms tit: of the switch havingthe contacts 84 are tensioned or cocked by the flexion thereof inresponse to engagement by the insulated tip 80 of the switch actuator orpush member 76. The capacitor 116 discharges substantiallyinstantaneously, and cannot recharge for a predetermined finite time dueto the resistor 116 Accordingly, immediately upon formation of thetyping impression, the switch arms 86 straighten out by virtue of theirresiliency, and thereby start the type bar back past the dashed lineposition to the dot-dash line position of Fig. 1. Release of the key 54allows the key lever Stl to return to its initial position under theinfluence of spring 58, and the jack or dog 60 thereby snaps under theshoulder 67. It will be appreciated that the size of the resistor 110 ischosen so that the capacitor 116 readily will recharge in the timebetween strokes of a typists fingers, but will not recharge sufficientlyrapidly to preclude return of a key bar 36 to its initial position.

It is further set forth in my aforesaid patent application that the sizeof the slug 44 may be varied from one type bar to another in accordancewith the area of the character of the associated type face. Forinstance, a larger slug is used in connection with the letter w," whilea smaller slug is used in connection with the point type face.

Without departing from the scope or structure of the invention as setforth in my aforesaid co-pending patent application, and as summarizedhercinabove, it is possible to obtain proportional letter spacing.Reference should "be had to Figs. 1-3 for an explanation thereof.

immediately beneath the position of the slug 44 when in the operativeposition shown in solid lines in Fig. 1, there is positioned a fluxconductor bar 122 having an enlarged lower portion in the form of ahollow cylinder 124. The flux conductor bar is made of soft iron or thelike, and is mounted in place by a support 126. Normally, the fluxconductor bar is positioned adjacent the lower left corner of the slug44 as viewed in the drawing. However, the support 126 is linked to thecarriage shift mechanism whereby to shift the flux conductor bar 22 to aposition beneath the lower right corner of the slug as shown in dashedlines. The plunger 128 is reciprocably mounted within the hollowcylinder 124 of the flux conductor bar, and is urged outwardly thereofby a compression spring 130. The bottom end of the plunger is pivotallyconnected at 132 to the end of a link or lever 134 pivoted at 136, andresting against a stop 137 which prevents the plunger 128 from beingforced completely from the cylinder by the spring 130. The pivotalconnection 132 preferably comprises a pin-in-slot connection forproviding a telescoping movement when the flux conductor bar 122 isshifted to the right to the dashed line position. The opposite end ofthe lever 134 is pivotally connected to a pawl or carriage escapementtooth 138 engaging with the rack 140 of the type generally found onsubstantially all conventional typewriters.

At the instant of printing, a certain amount of magnetic flux passesthrough the slug 44 into the flux conduct-or bar, and down to theplunger. The plunger ac,- cordingly is drawn up into the hollowcylinder, and in doing so pivots the lever 134 (in a clock-wisedirection as viewed in Fig. 1). This pulls down the carriage escapementtooth and allows the carriage to advance under the usual spring bias.When the capacitor 116 has discharged through the electro-magnet coil74, the magnetic pulse ends, and the spring forces the plunger 128 backto its normal lowered position, the tooth or pawl 138 thereby engagingthe rack 140, after the rack has advanced one or more tooth spaces.

It will be apparent that the amount of magnetic force determines thedistance the plunger 128 is drawn into the cylinder 124. Obviously, thegreater this distance, the longer the escapement tooth or pawl will beout of engagement with the carriage rack, and the further the carriagewill move along under the influence of its biasing spring.

Each slug 44 is formed individually so as to control the amount ofmagnetic flux that will be picked up by the conductor bar. Specifically,the amount of iron in the lower part of each type slug, and the width ofthe bottom edge of the slug, immediately adjacent to the upper end ofthe flux conductor bar, will be the main-controlling factor. Forexample, in the case of the letter In, .which is four units wide, therewill be four times the amount of iron in the lower part of the slug thatthere will be for the letter i, which is only one unit wide.Accordingly, the m type head will cause the plunger to be pulled-fourtimes deeper into the hollow cylinder of the conductor bar than for theletter i. Accordingly, the carriage escapement tooth or pawl will beheld out of engagement with the rack for four times as long, thusallowing the carriage to move along four units of space, as comparedwith one unit in the case of the letter i. It will be apparent that thespecific figures given are by way of illustration, since the non-linearcharacteristics of magnetic materials, and other factors, will requiresome variations from these figures.

The amount of iron in the lower portion of each slug substantiallydetermines the amount of carriage escapement. On the other hand, thetotal amount of ironin each slug determines the force of thecorresponding typing impression. Therefore, as will be seen in Figs. 3,4 and 7 it may reasonably be expected that theupper portion of a slug44, as is indicated at 44a, will be relatively wide, while the lowerportion 44b may be somewhat more narrow. The exact shape and proportionsof the upper and lower parts 44a and 44b may be expected to vary fromone slug to another. For example, the number 8 and the letter n are bothtwo units wide for spacing purposes. However, the numeral 8 covers aconsiderably larger area, and necessarily will be printed more forciblythan the n. Accordingly, there will be more iron in the upper part ofthe type slug for the number 8 than there will be for the letter n,although the amount of iron in the lowerpart 44b of the slug necessarilywill be about the same for the 8 as for the it since each is tworunits.wide, and the carriage must be allowed to escape the same distance foreach. i

In addition, the lower part of each slug is not necessarily uniform. histhe universal practice in typewriters to place the upper and lower casecharacters on the same type head, and to shift from one to the other byvertical movement of the carriage or thetype basket. For properproportional spacing, compensation must be made for the frequentlylarger size of the upper case or capital letters as compared with thelower case letters. For example, the lower case s may be two units widewhile the capital S is three units wide. A more extreme example is foundwherein the lower case f is only one unit wide, while the capital F isthree units wide. On the other hand, both cases of the letter M are fourunits wide.

Accordingly, there is provided a shit in the flux conductor bar as wellas in the carriage or type basket. As has been indicated, the slidingsupport 126 is connected to the carriage shift, so that in the event theplaten 30 is raised for the printing of a capital letter, the fluxconductor bar 122 will be shifted to the right to the dashed lineposition of Figs. 1 and 2. The amount of iron along the bottom edge ofthe slug is determined from front to back (or left to right as viewed inthe figures of the drawing) in accordance with the requirements of thecorresponding type face. Thus, in Figs. 3 and 4, it will be observedthat the left end of the lower part 44b of the type slug is of a givenwidth, while the right end d is of twice the width of the end c.Accordingly, when the flux conductor bar is positioned in the dashedline position for typing capital letters, twice as much flux will bepicked up by the conductor bar, as when the conductor bar is in thelower case or left hand position. Accordingly, the carriage will beallowed to escape twice as far when the flux conductor bar is positionedadjacent the end d, as when it is positioned adjacent the end c.

-It will be appreciated that when the flux conductor bar is nearer themain magnet, the flux will be stronger, and accordingly the end d maynot necessarily be quite twice as wide as the end c. The importantfeature with regard both to the necessary force for printing thecharacters, and for the character escapement, is that the slugs havevariable width and mass, both in the top portion, and in the lowerportion.

In Fig. there is illustrated a slug 44 wherein the ends 0 and d are ofthe same width in order to allow the carriage to escape the samedistance for the upper case as for the lower case characters.

As will be appreciated, the carriage escapement pawl or dog 138 may beretracted mechanically upon deprespedients could be used to achieve thedesired carriage movement as will be appreciated.

It is to be understood that the specific example of my invention asherein shown and described is set forth for purposes of illustration.Various changes in structure will no doubt occur to those skilled in theart, and are to be understood as forming a part of my invention insofaras they fall within the spirit and scope of the appended claims.

The invention is claimed asfollows: a a

l. A typewriter having a platen, a pivotally mounted type bar having atype face thereon, akey for pivoting said type bar towards the platen,and a carriage escapement, the combination comprising a magnetic slugcarried by said type bar, an electro-magnet acting on said slug uponenergization of said electro-magnet to urge the type face toward theplaten to form a typing impression, electrical circuit means forenergizing said electro-magnet, a magnetic operator positioned adjacentsaid slug when said electro-magnet acts thereon for activating saidoperator by magnetic flux passing through said slug from saidelectromagnet, and means operatively connecting said operator to saidcarriage escapement for operation thereof upon activation of saidoperator.

2. In a typewriter having a platen, a plurality of pivotally mountedtype bars each having a type face thereon, a plurality of keys forrespectively pivoting said type bar towards said platen, and a carriageescapement, the combination for proportional letter spacing comprising aplurality of magnetic slugs, each carried by one of said type bars, anelectro-magnet acting on any of said slugs upon energization of saidelectro-magnet to urge the corresponding type face toward the platen toform a typing sion of the spacer bar, as in the usual typewriter, or anauxiliary electro-rnagnetic device may be provided for this purpose.

When additional capacitors 118 are connected in the circuit for makingadditional copies, it is apparent that a greater magnetic force will beapplied to the flux conductor bar. However, the plunger cannot beallowed to enter this bar a greater than usual distance, or the carriagewould escape too far. Accordingly, a retarding spring 142 (Fig. 1) isstretched between the link or lever 134 and an anchor lever 144 which isvariable in position in accordance with the number of capacitorsconnected in the circuit. The anchor lever may be connected to theswitches 120, or independently operated. Other eximpression, electricalcircuit means for energizing said electro-magnet, a magnet operatorpositioned adjacent a slug being acted upon by said electro-magnet foractivating said operator by magnetic flux passing through said slug fromsaid electro-magnet, and means operatively con necting said operator tosaid carriage escapement for operation thereof upon activation of saidoperator, the size of each slug being individually determined to controlthe amount of flux passing therethrough.

3. The combination set forth in claim 2 wherein the magnet operator ispositioned adjacent a portion of each slug which is not facing theelectro-magnet, and wherein the operator is shiftable along saidadjacent portion in accordance with whether an upper case or lower casetyping impression is to be made, and wherein the area of said adjacentportion varies along the direction of movement of the operatortherealong, said area variation being in accordance with the variationin width of the lower case and upper case characters whereby to directgreater or lesser amounts of flux to said magnetic operator forcontrolling the operation of said carriage escapement in accordance withthe width of the character to be typed.

4. The combination as set forth in claim 2 wherein one face of the slugconfronts the electro-magnet and another face confronts the magneticoperator, the area of the electro-magnet confronting face beingdetermined in accordance with the area of the character being printed,and

the area and configuration of the operator confronting face beingdetermined in accordance with the width of the character being typed.

5. The combination as set forth in claim 4 wherein the magnetic operatoris reciprocably shifted along the confronting face of the slug inaccordance with the typing of a lower case or an upper case character,and wherein the area of the operator confronting face is determinedalong the path of movement of the operator in accordance with the widthof the upper case or lower case character being typed.

6. In a typewriter having a platen, a plurality of pivotally mountedtype bars having type faces thereon, a plurality of keys forrespectively pivoting said type bars towards said platen, and a carriageescapement, the combination comprising a plurality of magnetic slugseach carried by one of said type bars, an electro-magnet individuallyacting on any of said slugs upon energization of said electro-magnet tourge the type face toward the platen to form a typing impression,electrical circuit means for energizing said electro-magnet, a magneticflux conductor positioned adjacent the slug being acted on by theelectromagnet for conducting flux from said slug, the area of the partof each slug adjacent said flux conductor being determined in accordancewith the width of the character on the corresponding type face wherebyto direct an amount of flux into said conductor proportional to thewidth of said character, a magnetic member movable relative to said fluxconductor a distance proportional to the amount of flux in saidconductor, and means operatively connecting said member to said carriageescapement for effecting escapement of said carriage a distanceproportional to the distance which said member is moved.

7. In a typewriter having a platen, a movably mounted type bar having atype face thereon, a key for moving said type bar to bring said typeface into printing proximity to the platen, and a carriage escapement,the combination comprising a magnetic portion on said type bar, .anclectro-magnet acting on said magnetic portion upon energization of saidelectro-magnet with said type face in printing proximity to said platen,electric circuit means for so energizing said electro-magnet, a magneticoperator positioned adjacent said magnetic portion when saidelectromagnet acts thereon for activating said operator by magnetic fluxpassing through said type bar magnetic portion from saidelectro-rnagnet, and means operatively connecting said operator to saidcarriage escapement for operation thereof upon activation of saidoperator.

References Cited in the file of this patent UNITED STATES PATENTS2,512,825 Chambers June 27, 1950 FOREIGN PATENTS 129,801 Austria Oct.10, 1932

